Billiard table with reinforcement on structure and support for the heavy slate

ABSTRACT

A billiard table is enhanced by inserting an additional wood layer between the slate and the frame. Preferably, the additional wood layer is cut into two halves and placed on top of the frame such that there is space between the half boards. Slots are cut perpendicular to the longitudinal axis of the half boards to match the position studs on the interior beams. The angular table legs are enhanced by having the side boards of the legs cut at 45 degree angle at the connecting surface and creating a duct perpendicular to the connecting surface with a strip of wood glued into the duct running along the length of the leg. The table legs are further enhanced by inserting a strip of wood at the interior corner of the leg, forming a triangle with the two adjacent side boards. This invention reduces the overall cost of production.

CROSS-REFERENCE TO RELATED APPLICATIONS

This invention claims priority to a patent issued by the State Intellectual Property Office of the People's Republic of China, application number 200610066707.8, dated Oct. 12, 2006, which is hereby incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

Billiard game is very popular in the United States. The market for home billiard table is larger than that for commercial use. While home billiard tables resemble commercial tables in appearance and functionality, price is an important factor considered by consumers.

The components of an 8-foot billiard table commonly seen in today's market are depicted in FIG. 1. From bottom to top:

-   -   four table legs 100: pre-assembled before arriving consumers'         homes.     -   frame 101: consists of four pieces of wooden sideboard forming a         rectangle. The exterior surface of the sideboards could be         finished for a furniture look. To provide support, one or more         interior horizontal and vertical beams are added. Unlike the         sideboards, these beams could be made of less expensive         materials. After installing the table legs onto the frame, the         frame provides a flat and even surface to support the slate.     -   slate pieces 103, 104 and 105: Slightly bigger than the play         area of 4 ft×8 ft, the slate weighs about 530 lb. A 3-piece         slate is often used in home billiard table.     -   table rails 107, pockets 106 and table cloth (not shown)

A completely installed solid wood billiard table weighs between 950-1100 lb. The delivery of its heavy and bulky components through doors, thresholds, stairs and tight corners presents enormous challenge. Many of these places preclude the use of heavy duty lifting machines. Due to these reasons, components of home billiard tables are packed separately and the table is fully installed only after arriving at the consumer's home. Similarly, the slate, weighing at 530 lb, is often made of three individual pieces that are put together at the consumer's home.

Billiard tables are often packed and delivered in semi-assembled packages in which the components are partially assembled. Depending on the extent of assembly done before leaving the billiard table manufacturing site, there are two types of semi-assembled packaging: Semi-knock down kit (SDK) and complete-knock down kit (CDK).

A SDK consists of a pre-installed table frame (sideboards and interior beams) in one box while the slate pieces in another. Table legs and other components such as rails and pockets, are placed among the empty spaces within the table frame.

With the pre-installed table frame in a SDK, the frame top is adjusted to produce a leveled and even surface before arriving the consumer's home. The technicians only have to provide minimal service to complete installation of the billiard table at the home site. However, the size of the pre-installed table frame (about 8 ft×4 ft×16 in) makes transportation and delivery difficult.

A CDK, on the other hand, refers to the package in which the frame is not assembled. In other words, the sideboards and interior beams remain as separate pieces as are the table legs and other components of the table. Each piece is packed individually. This type of packaging provides flexibility in transportation and makes delivery to consumers' homes feasible. But the installing technicians face challenges in ensuring that the resulting frame top is even and leveled, and that the three-piece slate is assembled perfectly flat. Failure to do so will result in an unstable and dysfunctional billiard table. Under present technology, pegs of various sizes and thicknesses are inserted between the frame top and the slate to correct for any unevenness.

Material used in the table frame also plays a role in the final stability and functionality of the billiard table. Because of its sturdiness, hardwood is commonly used in frames of high-end billiard tables. Less expensive table frames are made of medium fibre boards or medium density fibreboards (MDF). Despite treatments like drying and sealing, the wood may warp over time, resulting in an uneven frame top and thus leaving spaces between the frame top and the bottom surface of the slate. Since the slate is often comprised of three individual pieces, an uneven frame top will prevent the slate pieces from forming a flat and leveled surface for billiard balls to roll freely.

The table legs must also be strong enough to support the weight of the table. With a weight of 950 lb-1100 lb for an 8-foot billiard table, each leg has to support up to 275 lb of static pressure. This creates challenge for polygonal plywood legs that are used in less expensive billiard tables. Glued together by three or more pieces of plywood, a polygonal plywood leg could only provide tear strength. When the vertical pressure from the table top becomes excessive, or when billiard players' weights translate into horizontal thrusts, the tear strength may be inadequate to hold the plywood pieces together, causing tearing at the joints.

To overcome the difficulties in transportation, delivery, assembly, and cost control, a billiard table with improved structure and support is needed.

BRIEF SUMMARY OF THE INVENTION

This invention involves a reinforced billiard table with an additional layer inserted between the frame top and slate, providing a well-fitted contact surface for the slate to sit completely flat and leveled. As a result, the installing technicians could assemble the billiard table at the consumer's home easily using the individual sideboards and interior beams.

Furthermore, this invention relates to the use of less expensive plywood or other processed wood coated with wooden film in constructing the table legs, reducing the overall cost of production and also indirectly reducing damage to the environment.

Furthermore, this invention allows the packing of the table frame components in CDK, allowing flexibility in space utilization during delivery and hence reducing overall cost of production.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1. An explosive view of a typical billiard table using field arts.

FIG. 2. A slate using field arts.

FIG. 3. An explosive view of a billiard table under this invention.

FIGS. 4A & 4B. Side views of uniformed and tapered table legs showing the structure and pressure vectors using field arts.

FIG. 5. A cross-sectional view of a reinforced table leg under this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is based on an 8-foot American style billiard table. The length refers to the longer side of the table (about 8 feet long) and the width refers to the side perpendicular to the length (about 4 feet long).

The slate, composed of three individual pieces, 203, 204 and 205 in FIG. 2, carries a surface area slightly larger than 8 ft×4 ft. The Billiard Congress of American mandates the thickness of the slate in a commercial billiard table to be no less than 1 inch.

This invention provides a secure table frame that will not deform in the course of transportation. One application of the invention is to place a wooden plate parallel to and between the table frame and the slate. The slight elasticity of the wooden plate absorbs the pressure and curve-in from the sideboards and interior beams generated by the discrepancy in their positions. The wooden plate therefore replaces the uneven table frame top with a continuously flat surface, allowing a perfect and complete contact between the wooden plate and the slate.

One embodiment of this invention is to use a single piece of hardwood board for the wooden plate. Another embodiment is to use medium density fibreboard (MDF) that is made of compressed wooden fragments being glued together. As the fibres of a MDF run in random directions, i.e. multi-directionally, changes in the environment including temperature and humidity will not cause the board to expand or contract in a single direction. Instead, the board expands or contracts uniformly as a whole. This important feature ensures that the slate remains flat and leveled, allowing pressure exerted onto the slate to spread evenly.

One embodiment of the invention is to have the MDF cut into two halves along its longitudinal axis (FIG. 3, 302). One or more slots are carved in an inward position along the cut on each half of the MDF (FIG. 3, 311). Position studs are placed at the top of the interior beams in such a way that each slot matches the corresponding position stud. These position studs help the technicians to quickly locate the proper position for the half boards. The length of the position stud is slightly longer than the sum of the length of the corresponding slots on the left and right halves of the MDF, ensuring that the two halves of the MDF are seated with a space of approximately 0.6 inch between each other. It should be noted that in FIG. 3, there are two interior beams along the transverse axis of the billiard table and thus two position studs are needed. For table frames with a different number of internal beams along the transverse axis, the number of position studs should be matched.

Using two half MDFs instead of one whole piece allows the use of MDF commonly available in the market that are of approximately the same size required in this invention, further reducing the overall cost of production. In addition, the longitudinal half boards provide continuity along the longitudinal axis of the billiard table. Since the slate pieces are typically cut and then put together along the transverse axis of the billiard table, continuity in the longitudinal axis of the supporting layer, the MDF half boards, rather then in the transverse axis is needed. Half boards cutting along the longitudinal axis can provide such continuity.

Furthermore, cavities are created on the surface of the MDF. These cavities provide the technician easy access to the bottom of the slate through the table frame even after the MDF half boards and the slate are in place. The technician may easily insert pegs between the MDF and the slate to fine tune the elevation of play area if needed. The cavities on the MDF also reduce the total weight of the billiard table and hence lower the cost of transportation.

FIG. 4A depicts the side view of a uniform rectangular table leg while FIG. 4B is that of a tapered leg. For simplicity, the detail structure of the top and bottom of the legs are not shown.

The uniform table leg in FIG. 4A carries a cross section area and shape more or less the same at the top as at the bottom. A rectangular uniform leg consists of four wooden boards enclosing an empty space in between (FIG. 4A, 400). When the table frame and slate are still, the major pressure exerted is vertical pressure vector 401. This is then transferred to the body of the leg as vertical pressure vector 403. If there are no overall unbalanced forces, there will not be any horizontal pressure vector. However, during the billiard game, players may lean on the table and create a horizontal pressure vector 402 (in addition to the vertical pressure vector) on the leg, which is then transferred to the body of the leg as horizontal pressure vectors 404. The horizontal pressure will eventually tear the wooden boards apart at the seams.

The tapered rectangular table leg in FIG. 4B carries a cross section area at the top larger than that at the bottom. Similar to the uniform leg, a rectangular tapered leg consists of four wooden boards enclosing an empty space (FIG. 4A, 410). When the table frame and slate are still, the major pressure exerted is vertical pressure vector 411, transferring to the table leg as vertical pressure vector 413. When billiard players lean on the table, an additional horizontal pressure vector 412 is created. The pressure is then transferred onto the leg body as vertical pressure vector 413 and horizontal pressure vector 414. The horizontal pressure eventually will tear the wooden boards apart at the seams.

The illustrations in FIGS. 4A and 4B above are also applicable to triangular, pentagonal, hexagonal and other polygonal legs.

An application of this invention is depicted in FIG. 5, showing a cross section area of a square uniform table leg. The figure is not drawn to scale in order to clearly illustrate materials of various thicknesses. The table leg is made of four sideboards 511 covered with a layer of decorative wood film 510. The side board and wood film are processed into a synthetic board and cut at 45 degree angle at the connecting surface. A duct running along the length of the table leg is created perpendicular to the connecting surface. A strip of wood 512 is inserted into the duct and all joints are glued together. Without the strip of wood, the side boards are held together only by tear strength. A strip of wood not only serves to fix the location of the side boards, but also to reinforce the connecting surface by adding shear strength to the side boards. In other words, the addition of a strip of wood at the connecting joint of the side boards allows the table leg to sustain horizontal pressure vectors 404 and 414 in FIGS. 4A and 4B, respectively.

Based on geometrical mechanics, triangle is the most stable geometric shape. To further reinforce side board 511 and bring the strength of a hollow leg up to similar level as that of the hardwood table frame, and to prevent deformation of the leg due to the vertical and horizontal pressures exerted, a triangular shape is introduced at the connecting surface of the side boards. This is achieved by adding a piece of wood 513 at each of interior corners of angular leg, forming a triangle at the corner.

This invention allows one to use table frames made of MDF that could be transported in individual pieces and yet able to support the heavy slate. This feature reduces the labor and time involved in installing the billiard table and thus lowers the costs of production. In addition, the invention allows the use of inexpensive but strong table legs to support the billiard table, further reducing the costs.

Although the description above contains many specifics, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the presently preferred embodiments of this invention. Therefore, it will be appreciated that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art. All structural and functional equivalents to the elements of the above-described embodiments that are known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the present claims. 

1. An enhanced billiard table including the legs; table frame formed by four side boards and one or more interior beams running along the length or width of the table; slate; and table rails, in which an additional layer is added in between the slate and table frame.
 2. An enhanced billiard table according to claim 1 wherein the additional layer between the slate and table frame is solid wood or Medium Density Fibreboard (MDF).
 3. An enhanced billiard table according to claim 2 wherein the additional MDF is cut into two halves along its longitudinal axis, and installed on top of the table frame such that there is space between the two halves running parallel to the longitudinal axis of the frame.
 4. An enhanced billiard table according to claim 3 wherein slots are carved inwards along the longitudinal cut of the additional MDF and position studs are placed on the interior beams of the frame to match the corresponding slots.
 5. An enhanced billiard table according to claim 4 wherein the length of the position stud is longer than the sum of the depth of the matching slots on each half MDF.
 6. An enhanced billiard table according to claim 2, 3, 4 or 5 wherein there are cavities in the additional MDF.
 7. An enhanced billiard table according to claim 6 wherein pegs are inserted in local areas between the slate and the additional MDF to adjust the height.
 8. An enhanced billiard table according to claim 1 wherein the table legs are made of four side boards cut at 45 degree angle at the connecting surface, wherein a duct is created perpendicular to the said connecting surface, wherein a strip of wood running along the length of the leg is glued into the duct.
 9. An enhanced billiard table according to claim 8 wherein the side board is covered by wood film.
 10. An enhanced billiard table according to claim 8 or 9 wherein a supporting strip is inserted at the interior corner of the table leg, forming a triangle together with the two adjacent side boards.
 11. A method of producing the enhanced billiard table according to claim 1 wherein an additional wood layer parallel to the table frame is inserted between the slate and table frame and supports the slate.
 12. A method of claim 11 wherein the additional wood layer is solid wood or MDF.
 13. A method of claim 12 wherein the additional MDF is cut into two halves along its longitudinal axis, and installed on top of the table frame such that there is space between the two halves running parallel to the longitudinal axis of the frame.
 14. A method of claim 13 wherein slots are carved inwards along the longitudinal cut of the additional MDF and position studs are placed on the interior beams of the frame to match the corresponding slots.
 15. A method of claim 11 wherein the table legs are made of four side boards cut at 45 degree angle at the connecting surface, wherein a duct is created perpendicular to the said connecting surface, wherein a strip of wood running along the length of the leg is glued into the duct. 